Needle driving mechanism for sewing machines



March 29, 1938. 1.. G. BOWMAN NEEDLE DRIVING MECHANISM FOR SEWING MACHINES Original Filed Sept. 27, 1955 2 Sheets-Sheet 1 T u W N rIIIILQ M m 3 W 0 5 a d w 0 w L March 29, 1938. 1 BOWMAN 2,112,531

NEEDLE DRIVING MECHANISM FOR SEWING MACHINES Original Filed Sept. 27, 1955 2 Sheets-Sheet 2 o i Iv (N c; f 1 N O a Q? 0 0 m ca .4 o 0 n 0 Q a Q v w [owe 62.50ZUMAN L Mi Patented Mar. 29, 1938 UNlTED STATES PATENT OFFICE.

NEEDLE DRIVING LIEGHANI SM FOR SEWING MACHINES Original application September 27, 1935, Serial No. 42,547. Divided and this application April 20, 1936, Serial No. 75,484

1 Claim.

This invention relates to new and useful improvements in sewing machines generally, but more particularly to the needle driving mechanism thereof.

This application constitutes a division of my co-pending application Serial No. 42,547, filed Sept. 27, 1935, for improvements in Sewing machines.

The principal object of this invention is to provide a needle driving mechanism which is extremely simple in construction.

Another object of the invention is to provide a novel bearing for the needle lever shaft.

With these and other objects in view which will more fully appear, the nature of the invention will be more clearly understood by following the description, the appended claim, and the several views illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a front elevation of a sewing machine embodying my invention,

Figure 2 is a partial top plan view thereof,

Figure 3 is a perspective view illustrating the driving connections for the needle, and

Figure 4 is a perspective view of the needle shaft take-up bearing.

Like reference numerals designate corresponding parts throughout the several figures of the drawings.

The sewing machine to which I have applied my invention, embodies a main frame including a base 5, a standard 6, an overhanging or laterally extending arm 1, and a sewing head 8 which is secured to the free end of said arm.

A main shaft 9 equipped with the usual handwheel l0 and drive pulley II is journaled in the arm and sewing head.

Considering the direction of feed of the fabric as being away from the operator, the head 8 is equipped with a forward extension providing a needle shaft bearing support portion IS, a complemental stitch forming mechanism support portion I! and a drive housing portion 3.

Rigidly secured to the under face of and projecting from the support portion I1 is a horizontal presser foot 20 having formed therein a longitudinal opening effective during the sewing operation to receive a ridge of material.

The stitch forming mechanism includes a reciprocatory needle 24 which is oscillatable angularly across the opening in the presser foot. The 5 needle is attached to a needle arm 25, and the latter is clamped as at 26 to the forward end of an oscillatory needle shaft 2'! which is journaled in a bearing sleeve 28 supported in the bearing support portion 16. It will be observed by ref- 10 erence to Figure 4 that the sleeve 28 has its end formed in the nature of a split clamp which facilitates the taking up of undesirable shaft clearance and thus tends to assure very accurate needle action. It will be understood that bear- 15 'ings with a thrust motion at one end wear unevenly, the wear appearing at the thrust end first. By taking up slightly at the split clamp end of my improved bearing sleeve 28 wear can be compensated for and the life of the bearing 20 materially prolonged. The bearing sleeve 28 being only partially split, the desired wear take-up adjustment may be effected without danger of binding the needle shaft 21. The needle shaft 21 is held against end play by a collar 30.

A crank arm 31 is secured to the needle shaft and is link-connected as at 32 to one end of a forked bell crank lever 33 which is pivoted as at 34 in the sewing head 8, the fork embracing a block and eccentric equipment 35 as shown in 30 Figure 3 so that the rotary motion of the main shaft 9 will be transmitted in the form of oscillatory motion to the needle.

It is of course to be understood that the details of structure and arrangement of parts may be 35 variously changed and modified without departing from the spirit and scope of my invention.

I claim:

In a sewing machine, the combination with an oscillatable needle shaft, a crank secured adjacent one end of the shaft, driving connections with the crank for oscillating said shaft, a sleeve providing rotative bearing for said shaft and split at the end thereof adjacent the crank, and means for contracting the split end of the sleeve for hearing adjustment purposes.

LOUIS G. BOWMAN. 

